In industrial generators, hydrocarbon fuel, such as coal is burned to create steam used to drive turbine generators. For a combustor to operate efficiently and to produce an acceptably complete combustion that generates bi-products falling within the limits imposed by environmental regulations and design constraints, all of the individual burners in the combustor must operate cleanly and efficiently and all post-combustion systems must be properly balanced and adjusted. Emissions of unburned carbon (i.e., loss-on-ignition (LOI) data), NOx, carbon monoxide and/or other bi-products are generally monitored to ensure compliance with environmental regulations and to ensure compliance with design constraints. See U.S. Pat. No. 6,389,330 incorporated herein by this reference.
As stated in the '330 patent, some emissions, such as the concentration of unburned carbon in fly-ash, are difficult to monitor on-line and continuously. In most cases, these emissions are measured on a periodic or occasional basis by extracting a sample of ash and sending a sample to a laboratory for analysis. Usually the sample of fly-ash is sent to an offsite lab where the sample is weighed, burned, and reweighed. The analysis may take days to a week or more. Most power plants do not have a chemical lab on-site and, due to the elapsed time for an analysis, the plant efficiency is frequently not at an optimum level. The '330 patent proposes monitoring the radiation emitted from a post-flame zone of the combustor and in response to a fluctuation component of the radiation and then calculating one or more combustion parameters.
The RCA 2000 residual carbon analyzer (M&W Asketeknik) is advertised to extract fly-ash from the flue gas via a cyclone and analyze it in a transducer using light. The result of the analysis is sent to the control room. See also U.S. Pat. Nos. 5,774,176 and 5,173,662 incorporated herein by this reference.
Still, it appears no prior system is able to measure loss-on-ignition (LOI) directly, on-site, continuously, automatically (e.g., without the need for operator intervention) and without the need for calibration.